bad tracks record on hard disk - CP/M

This is a discussion on bad tracks record on hard disk - CP/M ; Hi I was wondering if anyone knew where and what fornat was used for the bad track record in most CP/M hard disk implementations. Although, not for CP/M, I'm working on a machine ( Olivetti M20 ) that uses PCOS. ...

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  1. bad tracks record on hard disk

    Hi
    I was wondering if anyone knew where and what fornat
    was used for the bad track record in most CP/M hard
    disk implementations. Although, not for CP/M, I'm working
    on a machine ( Olivetti M20 ) that uses PCOS. I'm
    trying to bring up a hard disk on this machine but
    I think it expects to see a table on the disk with a
    map of the bad tracks.
    I've run the format operation but it tells me that it can't
    read the bad track information. I believe that for
    this machine, this data was originally on the hard drive,
    from the manufacture.
    The problem is that the disk I have was previously
    formatted with 256 byte sectors. The M20 uses 128
    byte sectors.
    If I know the location, on the disk, of the bad track information
    and the format of that data, I can recreate a table on
    the disk I'm using.
    Does anyone have this information for CP/M?
    Dwight


  2. Re: bad tracks record on hard disk

    On 10 May 2006 14:51:29 -0700, dkelvey@hotmail.com wrote:

    >Hi
    > I was wondering if anyone knew where and what fornat
    >was used for the bad track record in most CP/M hard
    >disk implementations. Although, not for CP/M, I'm working
    >on a machine ( Olivetti M20 ) that uses PCOS. I'm
    >trying to bring up a hard disk on this machine but
    >I think it expects to see a table on the disk with a
    >map of the bad tracks.
    > I've run the format operation but it tells me that it can't
    >read the bad track information. I believe that for
    >this machine, this data was originally on the hard drive,
    >from the manufacture.
    > The problem is that the disk I have was previously
    >formatted with 256 byte sectors. The M20 uses 128
    >byte sectors.
    > If I know the location, on the disk, of the bad track information
    >and the format of that data, I can recreate a table on
    >the disk I'm using.
    > Does anyone have this information for CP/M?
    >Dwight


    First, usually for hard disks it's not bad tracks but bad sectors.

    CP/M did not do bad track formatting or bad sectors. That was a
    BIOS functional problem left to the bios programmer. That said, there
    is no standard for CP/M bad sectors.

    Most I've seen presumed all tracks good and had a supply of
    replacement sectors that would be remapped using a table
    in the BIOS as partt of the hard disk code.

    Allison

  3. Re: bad tracks record on hard disk

    On 2006-05-10, dkelvey@hotmail.com wrote:
    > If I know the location, on the disk, of the bad track information
    > and the format of that data, I can recreate a table on
    > the disk I'm using.


    I'm no expert, but I have seen such information for RL01/RL02 disk
    packs. A quick google should bring it up.

    On those packs, the first few sectors of the last track contained a
    table describing the location of the bad sectors.

    Of course, that's easy for the RL01/RL02 because they're hard-sector
    disks. ST-506 disks might be formatted FM, MFM, or RLL. Makes it a bit
    hard for the manufacturer to store a bad block table on them.
    --
    roger ivie
    rivie@ridgenet.net

  4. Re: bad tracks record on hard disk

    wrote in message
    news:1147297889.246046.278840@q12g2000cwa.googlegr oups.com...
    > I was wondering if anyone knew where and what fornat
    > was used for the bad track record in most CP/M hard
    > disk implementations.


    All the machines I worked on, bad sector (not "track," that I ever saw)
    handling was done in BIOS and was pretty much machine dependent. As to the
    initial bad sector list, it was always printed on the top of the drive. I've
    got a 5.25" full height drive here (I use it as a door stop) and the table is
    on the top. It's a 5M drive and lists some 30 or so bad sectors.

    How it's formatted can be important too. I reused a few of these MFM drives
    with an RLL controller (in a PC) and had to translate the sector list to allow
    for the change in sectors per track.

    - Bill



  5. Re: bad tracks record on hard disk

    dkelvey@hotmail.com wrote:
    >
    > I was wondering if anyone knew where and what fornat
    > was used for the bad track record in most CP/M hard
    > disk implementations. Although, not for CP/M, I'm working
    > on a machine ( Olivetti M20 ) that uses PCOS. I'm
    > trying to bring up a hard disk on this machine but
    > I think it expects to see a table on the disk with a
    > map of the bad tracks.


    For CP/M we just used the disk as it came. There was a generalized
    system where a BLOCKS.BAD file was created and assigned all bad
    blocks on the drive. By marking the file as r/o and sys we could
    preserve it and prevent using bad areas. Never read that file.

    --
    Some informative links:
    news:news.announce.newusers
    http://www.geocities.com/nnqweb/
    http://www.catb.org/~esr/faqs/smart-questions.html
    http://www.caliburn.nl/topposting.html
    http://www.netmeister.org/news/learn2quote.html


  6. Re: bad tracks record on hard disk

    First, there isn't one. What Zenith did was to collect bad sectors into
    a hidden system file (can't remember the name, but something like
    BAD.SYS). But it was an issue that CP/M itself just ignored.

    Second, while you could do this for an MFM drive from the 1980's, there
    is no way for any OS (not even Windows XP) to know about or manage bad
    sectors on any IDE device. This is done entirely within the drive and
    it's transparent to the OS. The drive can even "move" sectors without
    the knowledge of the OS. Technology has moved this out of the realm of
    operating systems.


    dkelvey@hotmail.com wrote:

    > Hi
    > I was wondering if anyone knew where and what fornat
    > was used for the bad track record in most CP/M hard
    > disk implementations. Although, not for CP/M, I'm working
    > on a machine ( Olivetti M20 ) that uses PCOS. I'm
    > trying to bring up a hard disk on this machine but
    > I think it expects to see a table on the disk with a
    > map of the bad tracks.
    > I've run the format operation but it tells me that it can't
    > read the bad track information. I believe that for
    > this machine, this data was originally on the hard drive,
    > from the manufacture.
    > The problem is that the disk I have was previously
    > formatted with 256 byte sectors. The M20 uses 128
    > byte sectors.
    > If I know the location, on the disk, of the bad track information
    > and the format of that data, I can recreate a table on
    > the disk I'm using.
    > Does anyone have this information for CP/M?
    > Dwight
    >


  7. Re: bad tracks record on hard disk

    On Wed, 10 May 2006 22:34:12 -0400, CBFalconer
    wrote:

    >dkelvey@hotmail.com wrote:
    >>
    >> I was wondering if anyone knew where and what fornat
    >> was used for the bad track record in most CP/M hard
    >> disk implementations. Although, not for CP/M, I'm working
    >> on a machine ( Olivetti M20 ) that uses PCOS. I'm
    >> trying to bring up a hard disk on this machine but
    >> I think it expects to see a table on the disk with a
    >> map of the bad tracks.

    >
    >For CP/M we just used the disk as it came. There was a generalized
    >system where a BLOCKS.BAD file was created and assigned all bad
    >blocks on the drive. By marking the file as r/o and sys we could
    >preserve it and prevent using bad areas. Never read that file.


    Thats how I handle it too. It's easiest and the utility to read and
    test all sectors is then generic(works for all media).

    Allison


  8. Re: bad tracks record on hard disk

    On 10 May 2006 14:51:29 -0700, dkelvey@hotmail.com wrote:

    >Hi
    > I was wondering if anyone knew where and what fornat
    >was used for the bad track record in most CP/M hard
    >disk implementations. Although, not for CP/M, I'm working
    >on a machine ( Olivetti M20 ) that uses PCOS. I'm
    >trying to bring up a hard disk on this machine but
    >I think it expects to see a table on the disk with a
    >map of the bad tracks.
    > I've run the format operation but it tells me that it can't
    >read the bad track information. I believe that for
    >this machine, this data was originally on the hard drive,
    >from the manufacture.
    > The problem is that the disk I have was previously
    >formatted with 256 byte sectors. The M20 uses 128
    >byte sectors.
    > If I know the location, on the disk, of the bad track information
    >and the format of that data, I can recreate a table on
    >the disk I'm using.
    > Does anyone have this information for CP/M?
    >Dwight


    There was a utility findbad.com that verified sectors and those that
    were bad and not in use were assigned to a file. Periodically you ran
    it and it would lock out a couple of sectors a year.

    Ideally you would run it right after formatting the drive, to get the
    initial batch of bad sectors then once a year or so to pick up the
    others. As I recall it told you what files were occupying bad areas of
    the drive (wish windows 9x scandisk did this) so that you could
    immediately try to recover them to another drive, or delete them so
    that findbad could assign those sectors into its file.

    Good hard drive formatting utlities allowed entering of the bad sector
    table that they used to include with hard drives, so that you could
    avoid the bad sectors they found at the factory.

    I think with the Montezuma Micro hard drive utility, it would lock out
    entire tracks when entering the bad sector table. (Been 20 years or so
    since I had a 5 later 15 meg drive on my 4p).



  9. Re: bad tracks record on hard disk

    On Wed, 10 May 2006 21:51:29 UTC, dkelvey@hotmail.com wrote:

    > Hi
    > I was wondering if anyone knew where and what fornat
    > was used for the bad track record in most CP/M hard
    > disk implementations. Although, not for CP/M, I'm working
    > on a machine ( Olivetti M20 ) that uses PCOS. I'm> Does anyone have this information for CP/M?
    > Dwight
    >


    Under CP/M there was the utility findbad which makes a file called
    [UNUSED].BAD. That file lockedout the bad sectors.

    There are several version for CP/M 2.2 and CP/M+ and a version using
    RSX.

    http://oldcomputers.dyndns.org/publi...STARTER/FBAD58
    X.DOC
    http://oldcomputers.dyndns.org/publi...EL/SIGM/VOLS00
    0/VOL067/findbd54.asm

    I think I have a *.com fiele anywhere


    --
    Greetings

    Fritz Chwolka


  10. Re: bad tracks record on hard disk

    What you call Findbad was not a CP/M utility. If it didn't come with a
    generic copy of the OS, and didn't come from Digital Research, then it
    was one particular OEM's software, and quite possibly specific to one
    particular computer and/or one particular disk drive or controller.


    Fritz Chwolka wrote:
    > On Wed, 10 May 2006 21:51:29 UTC, dkelvey@hotmail.com wrote:
    >
    >
    >>Hi
    >> I was wondering if anyone knew where and what fornat
    >>was used for the bad track record in most CP/M hard
    >>disk implementations. Although, not for CP/M, I'm working
    >>on a machine ( Olivetti M20 ) that uses PCOS. I'm> Does anyone have this information for CP/M?
    >>Dwight
    >>

    >
    >
    > Under CP/M there was the utility findbad which makes a file called
    > [UNUSED].BAD. That file lockedout the bad sectors.
    >
    > There are several version for CP/M 2.2 and CP/M+ and a version using
    > RSX.
    >
    > http://oldcomputers.dyndns.org/publi...STARTER/FBAD58
    > X.DOC
    > http://oldcomputers.dyndns.org/publi...EL/SIGM/VOLS00
    > 0/VOL067/findbd54.asm
    >
    > I think I have a *.com fiele anywhere
    >
    >


  11. Re: bad tracks record on hard disk

    On Sat, 13 May 2006 21:36:41 GMT, Barry Watzman
    wrote:

    >What you call Findbad was not a CP/M utility. If it didn't come with a
    >generic copy of the OS, and didn't come from Digital Research, then it
    >was one particular OEM's software, and quite possibly specific to one
    >particular computer and/or one particular disk drive or controller.


    While it was not a DRI software item is was run under CP/M as a
    transient app. I have it and it's generic. It uses the BIOS IO
    vectors and it's very portable in that the interface under CP/M is
    very standardized. All of the information needed to get the
    geometry and read and write are standard calls. The actual
    file with the bad blocks allocated to it is however written using
    BDOS IO (CP/M standard filsystem calls).

    It's portable enough by testing that the same copy (binary) works for:

    -My AMPROLB+ for the 3.5" 781k floppy, the SCSI 45mb HD.
    - SB180 using both floppy and SCSI bridge to MFM disk
    -Both kaypros (a II and turborom 4/84),
    -All of the S100 crates (Horizon II/hard sector, homebrew disk based,
    and Compupro),
    -Visual 1050 both floppy and SASI disk (under cpm-3).
    -It even works fine under MyZ80 though it will never see errors
    there as the PC hides them.

    Thats a sufficiently diverse group to say yes it works. If anything
    I'd call it a good example of a well written CP/M utility.


    Allison

    >
    >
    >Fritz Chwolka wrote:
    >> On Wed, 10 May 2006 21:51:29 UTC, dkelvey@hotmail.com wrote:
    >>
    >>
    >>>Hi
    >>> I was wondering if anyone knew where and what fornat
    >>>was used for the bad track record in most CP/M hard
    >>>disk implementations. Although, not for CP/M, I'm working
    >>>on a machine ( Olivetti M20 ) that uses PCOS. I'm> Does anyone have this information for CP/M?
    >>>Dwight
    >>>

    >>
    >>
    >> Under CP/M there was the utility findbad which makes a file called
    >> [UNUSED].BAD. That file lockedout the bad sectors.
    >>
    >> There are several version for CP/M 2.2 and CP/M+ and a version using
    >> RSX.
    >>
    >> http://oldcomputers.dyndns.org/publi...STARTER/FBAD58
    >> X.DOC
    >> http://oldcomputers.dyndns.org/publi...EL/SIGM/VOLS00
    >> 0/VOL067/findbd54.asm
    >>
    >> I think I have a *.com fiele anywhere
    >>
    >>



  12. Re: bad tracks record on hard disk

    On 2006-05-14, Allisonnospam@nouce.bellatlantic.net wrote:

    > On Sat, 13 May 2006 21:36:41 GMT, Barry Watzman
    > wrote:
    >
    >>What you call Findbad was not a CP/M utility. If it didn't come with a
    >>generic copy of the OS, and didn't come from Digital Research, then it
    >>was one particular OEM's software, and quite possibly specific to one
    >>particular computer and/or one particular disk drive or controller.

    >
    > While it was not a DRI software item is was run under CP/M as a
    > transient app. I have it and it's generic. It uses the BIOS IO
    > vectors and it's very portable in that the interface under CP/M is
    > very standardized. All of the information needed to get the
    > geometry and read and write are standard calls. The actual
    > file with the bad blocks allocated to it is however written using
    > BDOS IO (CP/M standard filsystem calls).
    >
    > It's portable enough by testing that the same copy (binary) works for:
    >
    > -My AMPROLB+ for the 3.5" 781k floppy, the SCSI 45mb HD.
    > - SB180 using both floppy and SCSI bridge to MFM disk
    > -Both kaypros (a II and turborom 4/84),
    > -All of the S100 crates (Horizon II/hard sector, homebrew disk based,
    > and Compupro),
    > -Visual 1050 both floppy and SASI disk (under cpm-3).
    > -It even works fine under MyZ80 though it will never see errors
    > there as the PC hides them.
    >
    > Thats a sufficiently diverse group to say yes it works. If anything
    > I'd call it a good example of a well written CP/M utility.


    It also works on the Epson QX-10 and QX-16 computers.

    --

    John (john@os2.dhs.org)

  13. Re: bad tracks record on hard disk

    Hi
    Yes, it usually just maps out bad sectors and not trakes.
    I've been trying to get a ST251 to work but It acts like it
    expects to see some sector(s) with this information. It
    is most likely expected from the manufacture of the origonal
    disk.
    The more I look into things, the more I think I have other
    problems first. The controller seems to be trashing all the
    sectors when trying to format. I've been writing some low
    level code to format a track but not getting the best results
    yet. I've already found dependencies on the specific drive
    in this controller. It expect a signal on pin 5 of the data connector.
    The ST251 has nothing connecter there. There may be other
    things as well.
    I've resorted to looking at short burst of write data with my
    non-memory type analog oscilloscope. I'm making progress
    so it doesn't look too bad.
    If I get clean formatting I suspect that I can figure out the bad
    sector record. I've seen several that will put the FFFF record
    to indicate the end of the records. Once I get the format working,
    writing FFFF to the first few sectors should make the machine happy.
    Dwight


  14. Re: bad tracks record on hard disk

    On 15 May 2006 16:03:30 -0700, dkelvey@hotmail.com wrote:

    >Hi
    > Yes, it usually just maps out bad sectors and not trakes.
    >I've been trying to get a ST251 to work but It acts like it
    >expects to see some sector(s) with this information. It
    >is most likely expected from the manufacture of the origonal
    >disk.
    > The more I look into things, the more I think I have other
    >problems first. The controller seems to be trashing all the
    >sectors when trying to format. I've been writing some low
    >level code to format a track but not getting the best results
    >yet. I've already found dependencies on the specific drive
    >in this controller. It expect a signal on pin 5 of the data connector.
    >The ST251 has nothing connecter there. There may be other
    >things as well.
    > I've resorted to looking at short burst of write data with my
    >non-memory type analog oscilloscope. I'm making progress
    >so it doesn't look too bad.
    > If I get clean formatting I suspect that I can figure out the bad
    >sector record. I've seen several that will put the FFFF record
    >to indicate the end of the records. Once I get the format working,
    >writing FFFF to the first few sectors should make the machine happy.
    >Dwight


    What machine is that. Most will operate with a null table.
    Format should not care of there is bad block info as once written
    you should go back anyway and run a test of the disk too see if any
    new bad block appeared.

    FYI: most st251s are suspect, heat is bad news for them and
    their lifetimes were usually short.


    Allison

    Allison

  15. Re: bad tracks record on hard disk

    On 2006-05-15, dkelvey@hotmail.com wrote:
    > The more I look into things, the more I think I have other
    > problems first. The controller seems to be trashing all the
    > sectors when trying to format. I've been writing some low
    > level code to format a track but not getting the best results
    > yet. I've already found dependencies on the specific drive
    > in this controller. It expect a signal on pin 5 of the data connector.
    > The ST251 has nothing connecter there. There may be other
    > things as well.


    This is probably a stupid question, but are you certain you're not
    dealing with an ESDI controller? They had different pinouts; on ESDI,
    pin 5 of the radial cable is listed as "reserved for step mode" over on
    pinouts.ru.
    --
    roger ivie
    rivie@ridgenet.net

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